Leather-degreasing process



A. J. HANGLIN LEATHER DEGREAS ING PROCESS Oct. 13

Original Filed Dec. 6, 1919 Patented oai. 13, 1925-.

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Application led December 6', 1919,-Seria1 .ll'o-.IMSQ Blj` RenewedIarchjfim. A

ToaZZ whom/jt may concern; I I Be it known'thatl I, ALBERT J. HANGLIN,

acitizen of the United States,- residing at Newark, New Jersey, haveinvented certain new andfuseful Improvements-in Leatherof materialssuch-as theskins and ide's o t greasing o vil .ing is a clear, full,fandexact description.

Degreasing Processes, of. which the' follow- This invention relates tothe de easin animals and sh, andV particularly to Hic deraw, wetcondition before being subjected tothe limingvor tanning processes, andthe invention has for its general object -an improved process foreffecting the degreasing ofthe aforementioned. and other materialsandfor conserving and recovering the.sol-- vent employed and the greaseremoved.

' apparatus being shown on the accompanyprocess of this invention;

' that is, as they are Heretofore it has been customary to e'ect thedegreasing of skins to'be tanned'after the liming operation, andso faras I am aware, no' successful process' or means has ever before beendevised for degreasing skins or hides in their raw wet conditiontakenromthefanimal or fish, and also skins which have been salted, pickled,or otherwise treated b the packer, butcher, or other person who oldsthem in s uch a condition that putrefaction will not take place' beforethe skins `are treated by the tanner. Thelprocess is also applicable todry hides or skins which have not been treated by the tanner? In carryinout thel novel process, I preerably eploy apparatus suc as that hereinillustra and which. constitutes a part of the present invention, thisdegreasing in` sheet of drawings in which ig. A1 is a side elevation ofthe essential parts of the apparatus for carrying out Lthe Fig. 2 is alongitudinal drum having a perfora false bottom 12 Y between which. andthe outer wall. of the drum a steam pipe Mis-located, this pipebeing'connectedthrough the hollow trunnion 4 by a connection 16 (allow'the'ppe 14 to revolve with the ilrum), lh a pipe 18 f' such materialswhen in their'-v pulley 32 connected ing to a storage tank t0 pass fromlan Sgply -connected to t e pipe 68 and controll by section through therotatable drum, in which the main Stepfrom the condenser valve 82 insaid pipe from any .suitable source ofsteamsupply l' f'- age for the sovent and its contained grease and water, an air intake Apet cock 26 andYwith a drainage cock 28 for the steam and the dium is "al'so rovidedwith a drainpipe ,14.- Within the drui'irare paddlesor l aillepplates 30which serve to insure ofthe material to ,be degreased with the solventwhen the drum rotates. 'A driving of power may serveto elect therotation of the drum.

' Through the. other hollow trunnion 6 ofv ther drum, the interior ofthe' drum is rotatably connected by a union 34. with apipe 36, whichinturn isV connected by a double 'll-joint 38 .with a ipe 4'0` leadingto a condenser coil 42; .wit a second pi 46, and with a third pipe4811eadin to a still 50, the condenser coil 42 Abeing so connectedthrough apipe 51'- with the storage tank `46. By means of .cocks 52, 54and 5 6, -thevarious operative The storage tank 46 is connected by apipe 58 to a vacuum pump 60,l which discharges through a 4pipe'62 into adischarge throughsaidpump 60. The storage 46 is. surround through whichcold water may be caused suitable source of to any suitable source Atank 64 h containing any suitable material or chemical 'for recoveringvapors Vwhich may N pass 44 leadconnections between the 36'and the otherpipes hereinafter to described maylbe effected.'

ed by a water jacket-66 the cock 70, this water preferably then passingvthrough 4a'pipe`72 into the condenserA tank 74 enclosing the condensercoil 42, and

76 to the discharge.

tank through an` outlet' pliebe still 50 is surrounded by a steam jacket78 connected by a pipe180 to n suit- 4 able source of steam supplycontroll by'a erably provided with severalfpet cocks 84, 86 and 88 topermit the entrance of air, and

,andthisstll'ispref-v ics with a valve 94.

Ainto the still 50, this pipe' being provided The storage tank 46 ispreferably provided with a vacuum gage 9 6 and a vacuum relief pet cock98, and the connection 5l between the condenser and the-storage tank ispreferably provided with a sight glass 100.

In carrying out the novel process `of this invention with the novelapparatus just described, the hides or skins to be degreased areintroduced into the drum 2, through the opening 23, normally closed bythe door 22, together with the solvent, a, suitable proportion, whennaphtha is used as a solvent, being about 35. gallons of naphtha foreach 100 pounds of wet hides or skins. In order to produce the internalvpressure in the drum, which is one of the lmportant novel i features ofthe process of this invention, the

naphtha is preferably introduced into-the drum at a temperature belownormal room temperature, say about 60 F., andthe drum is then closed andsealed air-tight and is set in rotation. Heat is then applied throughthe steam pipe 14 until the' temperature of the contents of the drum hasbeen raised to approximately 80 F., thereby attaining an internalpressure of about 3 pounds, due to the expansion of the air and thenaphtha.

The agitation of the contents of the drum, while subjected to thisinternal pressure, by the continued rotationv of -the drum, causes thenaphtha to penetrate the hides or skins and partly to dissolve andpartly to emulsify the grease and to displace so-m'e of the water in thehides or skins.

The drum is rotated for a suitable length of time, the length of timenaturally varying with the size of the drum and with the amount andthickness 'of 'the material treated. I have found the time required tovary from 15'minutes to an hour, in ac-4 cordance with-the varyingconditions just enumerated.

After the drumhas been rotateda suitable len h of time, it is stopped,the drain cock 24 1s vconnected with the pipe 92, and the liquid isdra-wn olf into the still 50, all valves in the drum being preferablyopened to allow free ingress of air to facilitate the draining of theliquid.l lVhen the draining is completed, the drum is disconnected fromthe still, the drain cock 24 closed, the same quantity of fresh coldnaphtha. as used in the lirst instance is introduced into the drum, and.the operation repeated. The liquid is then again drawn off into thestill through the drain cock' 24 and pipe 92, and all valves againclosed and, the vacuum pump vbeing in operation,. the drum is revolvedand the valve 52 on' the pipe 36 leading to the vacuum pump through thepipe 40, condenser coil 42, pipe 51, storage n tank. 46 and-pipe 58 isopened, the valves 456 and 54y being closed, and this connectionv 2 inavolune so small that it Will not overcome more than two or three inchesof vacuum, the pump 60 being maintained in operation. The pump 60 isthen continued in operation until allnaphtha vapors are removed from thedrum 2; this operation usually taking from 15 minutes to an hour, andthe result may be observed in the sight glass 100. This completes thedegreasing operation and the drum is opened and the contents areremoved.

-To recover the solvent from the still 50, the liquid `'and semi-solidmaterial which has beenI drained from the drum 2 into the still areheated until most of the volatile solvent is driven'off through thepipes 48, 40' and condenser-pipe 42 mto the storage tank 46, the still5() being heated by the steam jacket 78. In order to recover still moreof the solvent, the still is connected with the vacuum pump through thestorage tank and condenser, the valves in the still' are closed, and thepump vis operated until a maximum vacuum is attained in the still. Thepet cocks 84,86 and .88 on the bottom of the still are" then opened andair is admitted in volume suicient to maintain within four or liveinches of maximum vacuum While the pump is continued in operation, thisoperatlon being continued until all the solventis removed. The still ispreferably provided with a cup connection 102 to facilitatewashing outof the still, this connection being normally closed by valve 104. Thegrease in the still may be drawn off through the drainage cock 90. Anyvapors which pass through the vacuum pum 60 may be recovered in thedischarge ta 64 by providing suitable chemicalsor other means foreffecting combi-nation or condensation.

From the foregoing description of the novel degreasing process and theapparatus for practicing this process, some ofthe advantages oftheprocess will be apparent. By treating raw. Wet hides and skins underpressure accompanied by agitation, I secure a vpractically completeremoval of grease, something that has not heretofore been done with wetmaterial, such as pigskins, sheepskins, goatskins, dogskins, seal andporpoise skins, and the other raw skins used in thel -tanning industry.

The advantage of removing the grease before the tanning operation isbegun will be obvious to those lskilled-in the art, such removal Servingto effect a shortening of the time required for liming in the beamhousee'ect of caustic lime and sodium sulphide because of the fact that thematerials used can more rapidly attack the hair cells of the degreasedhide and thus permit the removal of the hair or wool is important sinceit lessens'the harmful on the raw hides or skins, resulting -thereforein the production of a iner and stronger leather in a shorter time thanlby processes heretofore practiced. The process also is more economicalof solvent than processes heretofore used, and `a greater-percentage ofgrease is recovered in a usefulY form. Upto the present` time' mostsheepskins and many other kinds offskins have been onlypartiallydegreased before tanning. Vha't grease has been left in the skins, if itinterferes' with the roper finishing of the leather, is removed a terthe tanning process, being usually removed from the dry tanned leather.This pract'ce results also in the re'- inoval of the grease and oilswhich the tanner has used in his processes. Moreover, as. naphtha doesnot dissolve alkalis, these .if used in conjunctionl with oils or soapin' the stuiiing or fat liquoring treatment ofthe `weaken 1t.

the leather and subseleather are left in the leather fibre and quently 0act upon' When my process is employed, the de'- greasing of the tannedleather is'not necessary, and therefore the greases and oils used instuing are rnot removed, the quality of the resultant leather istherefore better, and the danger of injury to the leather bytheexcessive heat sometimes employed with processes now in use is avoid Itwill be understood that the process may.

be practiced with any suitable grease sol- "vent, vsuch as na lcarbonbi'sulphl e,

in a shorter time. Thisy be understood that f That Vimprovement in fish,

- -Signed at Newark, New Jersey,

htha, carbon tetra-chloride, tetra-chlorfethylene, these solvents beingcapable of dissolving animal and fish oils and grease and yemulsifyingthem under the conditions produced with the apparatus herein described.To facilitate continuous operation, it will a battery of degreasingdrims may be associatedwith a single pump, still, condenser and storagetank, such an obvious modification of the structure hereinshown notrequiring special illustration.

1 Although the invention is particularly described in connection withthe degreasing of itis obvious that the process maybe utilizedin'degrea'sing other materials, such, for eX- ar'nple, as wool.

^ What I claim as new is:

he art of degreasing raw wet skins or hides of animals and whichconsists in enclosing the material .to'be degreased and areadilyvolatiliz'- able grease solvent in a-drum, sealing-the j drumair tight,raising the temperature of. the drum contentsto a degree to meure theproduction of substantial pressure in the drum, the vinitial temperatureof the drum contents being such that the temperature required to producesuch pressure will not be so high as to injure the skins or hides, thenagitating the drum contents, while lmaintaining the internalpressure, toeffect a solution or emulsion ofthe'greasa-and then removing the solventwith its contained grease and water.

this 2nd day of December, 1919. f

^ ALBERT J. HANGLIN.

raw wet skins I,or hides of animals and fish, v

